﻿// Copyright 2013 Ronald Schlenker, www.technewlogic.de.
// 
// This file is part of Byond.
// 
// Byond is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 2 of the License, or
// (at your option) any later version.
// 
// Byond is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.
// 
// You should have received a copy of the GNU General Public License
// along with Byond.  If not, see <http://www.gnu.org/licenses/>.
using Autofac;

namespace Byond
{
	public sealed class RuntimeScope
	{
		private readonly ILifetimeScope _lifetimeScope;
		
		private ILifetimeScope _currentScope;
		private ILifetimeScope _futureScope;

		public RuntimeContext Current { get; private set; }
		public RuntimeContext Future { get; private set; }
		public RuntimeContext MostFuture { get; private set; }

		public void Reset()
		{
			if (_futureScope != null)
				_futureScope.Dispose();
			_futureScope = null;
			Future = null;

			if (_currentScope != null)
				_currentScope.Dispose();
			_currentScope = _lifetimeScope.BeginLifetimeScope();
			Current = _currentScope.Resolve<RuntimeContext>();
			MostFuture = Current;
		}

		public void PrepareFutureContext()
		{
			if (_futureScope != null)
				_futureScope.Dispose();
			_futureScope = _lifetimeScope.BeginLifetimeScope();
			Future = _futureScope.Resolve<RuntimeContext>();
			MostFuture = Future;
		}

		public void ApplyFutureContext()
		{
			if(_currentScope != null)
				_currentScope.Dispose();
			_currentScope = _futureScope;
			_futureScope = null;
			Current = Future;
			MostFuture = Current;
			Future = null;
		}

		public void DiscardFutureContext()
		{
			_futureScope = null;
			MostFuture = Current;
			Future = null;
		}
	}
}
